Knocking Sound

Larz · 09-25-2014, 06:13 PM

New owner here having recently acquired a 2011 e90 M3 6MT a few months ago. While I love the car, I've had a few issues (bad 02 sensor, plugs and air pump) and things have been running great for a few weeks until I just noticed a knocking sound.

It doesn't seem to be coming from engine but rather underneath and on the driver's side. I only seem to notice it at idle and it's irregular. Sounds like knocking on plastic or like when you have some change in a laundry dryer. If I restart the car it starts back up after a minute.

Luckily the car is CPO with original warranty so I'll be contacting the dealer but wondering if anyone could identify it.

Here is a crummy video. Couldn't here it until I moved my phone near the wheel well:

///M Power-Belgium · 09-25-2014, 06:31 PM

No worries !
This is no bearing failure ,it sounds like there is something loose that knocks against something, you need a close look under the car .

BPMSport · 09-25-2014, 07:18 PM

Check the belts.

MFL · 09-25-2014, 08:01 PM

Flywheel Chatter?

Larz · 09-26-2014, 08:19 AM

Thanks. Yes, I think something may be loose. After cold start this morning, the sound was more of a rattle that was even vibrating through the dash. After the car warmed up, the rattle was replaced by the knocking sound again.

Having it looked at this afternoon so we'll see.

mkPOTO · 09-26-2014, 09:38 AM

its your pulley/belt. Had the same issue, replaced the belt and tightened up the pulley and boom it went away

09-25-2014, 06:13 PM	#1
Larz New Member 1 Rep 15 Posts Drives: E90 M3 Join Date: Apr 2013 Location: United States iTrader: (0)	Knocking Sound New owner here having recently acquired a 2011 e90 M3 6MT a few months ago. While I love the car, I've had a few issues (bad 02 sensor, plugs and air pump) and things have been running great for a few weeks until I just noticed a knocking sound. It doesn't seem to be coming from engine but rather underneath and on the driver's side. I only seem to notice it at idle and it's irregular. Sounds like knocking on plastic or like when you have some change in a laundry dryer. If I restart the car it starts back up after a minute. Luckily the car is CPO with original warranty so I'll be contacting the dealer but wondering if anyone could identify it. Here is a crummy video. Couldn't here it until I moved my phone near the wheel well: Last edited by Larz; 09-25-2014 at 06:15 PM.. Reason: Can't seem to upload video
	Appreciate 0 Tweet Quote

09-25-2014, 06:31 PM	#2
///M Power-Belgium General 63077 Rep 24,610 Posts Drives: ///M3-E92-DCT Silverstone II Join Date: Jul 2012 Location: Belgium iTrader: (0)	No worries ! This is no bearing failure ,it sounds like there is something loose that knocks against something, you need a close look under the car . __________________ "MAX VERSTAPPEN" IS THE 2021+2022+2023 F1 WORLD CHAMPION - #UnLeashTheLion BPM DEV-Tune & DCT Software-Tune & Servotronic & coding ///Alpine HID Angeleyes ///Oem.exhaust mod.
	Appreciate 0 Quote

09-25-2014, 07:18 PM	#3
BPMSport BimmerPost Supporting Vendor 3387 Rep 7,541 Posts Drives: Harrop M3 / F10 M5 / F82 M4 Join Date: Apr 2008 Location: SoCal iTrader: (9) Garage List 2000 BMW M5 [0.00] 1990 BMW 735i Turbo [0.00] 2008 BMW M3 [7.50] 2015 BMW M3 [0.00] 2015 BMW M5 [0.00]	Check the belts. __________________ -----\| Like us on Facebook \| Instagram \|\| Tuning Information \| Remote Coding \|----- ----Visit us at www.BPMSport.com - Emotion. Driven. \| Toll Free: (888) 557-5133----
	Appreciate 0 Quote

09-25-2014, 08:01 PM	#4
MFL Major 174 Rep 1,246 Posts Drives: E92 M3 Join Date: Sep 2013 Location: Bellevue, WA iTrader: (3) Garage List 2010 BMW M3 [9.00]	Flywheel Chatter?
	Appreciate 0 Quote

09-26-2014, 08:19 AM	#5
Larz New Member 1 Rep 15 Posts Drives: E90 M3 Join Date: Apr 2013 Location: United States iTrader: (0)	Thanks. Yes, I think something may be loose. After cold start this morning, the sound was more of a rattle that was even vibrating through the dash. After the car warmed up, the rattle was replaced by the knocking sound again. Having it looked at this afternoon so we'll see.
	Appreciate 0 Quote

09-26-2014, 09:38 AM	#6
mkPOTO Mr. Nice Says Hello 635 Rep 16,662 Posts Drives: BMW M3 \| X5 xdrive 35i MSport Join Date: Dec 2008 Location: USA iTrader: (25) Garage List 2002 Lexus GS300 [0.00] 2008 BMW E92 M3 [5.58]	its your pulley/belt. Had the same issue, replaced the belt and tightened up the pulley and boom it went away
	Appreciate 0 Quote